Analyte detection in physiological fluids, e.g. blood or blood-derived products, is of ever increasing importance to today's society. Analyte detection assays find use in a variety of applications, including clinical laboratory testing, home testing, etc., where the results of such testing play a prominent role in diagnosis and management in a variety of disease conditions. Analytes of interest include glucose for diabetes management, cholesterol, and the like. In response to this growing importance of analyte detection, a variety of analyte detection protocols and devices for both clinical and home use have been developed.
One type of system that allows people to conveniently monitor their blood glucose levels includes a sensor (e.g., a disposable test strip), for receive a blood sample for a user, and a meter that “reads” the test strip to determine the glucose level in the blood sample. The test strip typically includes an electrical contact area at one end for mating with the meter and a sample chamber at the other end that contains reagents (e.g., glucose oxidase and a mediator) and electrodes. To begin the test, the test strip is inserted into the meter and the user applies a blood sample to the sample chamber. The meter then applies a voltage to the electrodes to cause a redox reaction and the meter measures the resulting current and calculates the glucose level based on the current. After the test, the test strip can be disposed.
It should be emphasized that frequent measurements of blood glucose levels may be critical to the long-term health of many users. As a result, there is a need for blood glucose measuring systems that are easy to use. One improvement in blood glucose monitoring has been a reduction in the volume of sample needed to perform a test, which reduces the trauma associated acquiring blood samples. However, as sample sizes become smaller, the dimensions of the sample chamber and electrodes in the test strip also become smaller. This, in turn, may make test strips become more difficult to handle.
One solution has been the use of cassettes that hold a series of test strips (e.g., a dozen) that can be mechanically fed from the cassette into a meter without handling by a user. For example, one such cassette has a circular configuration with axially positioned test strips, through a complicated mechanized procedure, individual test strips are rotated into position and fed into the meter. Unfortunately, such systems can require complex mechanical structures that result in added expense and unwanted bulk.
Accordingly, there is a need to for blood glucose measuring systems with features for measuring blood glucose levels conveniently and reliably.